Concurrent BLE scanning and initiation for bandwidth efficiency and power saving

ABSTRACT

A technique to open a single receiving window to perform scanning and initiating operations in a Bluetooth Low Energy compliant device, instead of using two separate receiving windows to perform the equivalent operations. The combining of the scanning and initiating operations in one receiving window, instead of two separate windows, reduces power consumption and provides for bandwidth efficiency.

BACKGROUND OF THE INVENTION

Technical Field of the Invention

The embodiments of the invention relate to wireless communications and,more particularly, to linking of devices that utilize Bluetooth™technology.

Description of Related Art

Bluetooth™ (hereinafter “BT”) wireless technology is a short-rangecommunications system utilized to wirelessly link portable and/or fixedelectronic devices, such that cables and wires that would normallyconnect theses devices are not needed. Presently, there are two forms ofBT wireless technology systems. One form of BT is the Basic Rate (BR)system, which is also referred to as classic Bluetooth, since thissystem has been in existence for some time and currently implemented inwirelessly connecting devices. The second form is a newer implementationof BT, known as Low Energy (LE) BT or Bluetooth Low Energy (BLE). Bothsystems include device discovery, connection establishment andconnection mechanisms.

The Basic Rate system includes optional Enhanced Data Rate (EDR)Alternate Media Access Control (MAC) and Physical (PHY) layerextensions. The Basic Rate system offers synchronous and asynchronousconnections with data rates of 721.2 Kbps for Basic Rate, 2.1 Mbps forEnhanced Data Rate and high speed operation up to 24 Mbps with the IEEE802.11 AMP (Alternate MAC PHY) systems. The BLE system includes featuresdesigned to enable products that require lower current consumption,lower complexity and lower cost than classic BT using BR/EDR. The BLEsystem is intended to consume a fraction of the power required forclassic BT and a device powered by a button cell battery may power BLEcommunications for an extended period from the battery. A number ofdifferent applications are envisioned for BLE, including medicalmonitoring and transmission of the monitored data by a wireless link.

Both classic BT and BLE systems generally operate in the unlicensed 2.4GHz ISM (Industrial, Scientific, Medical) band, typically utilizing oneof the IEEE 802.11 protocols (e.g. 802.11a/b/g/n). Both Bluetooth formsare further described in the Bluetooth Specification, such as BluetoothSpecification Version 4.0, Volumes 0-6, published Jun. 30, 2010, whichis incorporated by reference herein.

In the BT 4.0 specification for BLE operation, there are five statesthat a BLE device may be in, of which one is a standby state. In thisspecification, the BLE scanning and initiation states are specified astwo independent and completely separate activities (states). A BLEdevice which is compliant to the BT 4.0 specification standard doeseither scanning or initiation. The scanning state is entered to scan foradvertisers on a BLE network, while the initiation state is entered toinitiate a connection request. Accordingly, in order to perform bothfunctions of scanning and initiating, a BLE device needs to open areceive window a minimum of two times (one receive window for scanningand one receive window for initiating).

When the receive window is open on a device, the device is in areceiving mode for BLE and the radio frequency (RF) front end of thedevice, as well as the antenna, may be occupied strictly with thereceiving function. This implies that during these two receive periodsfor scanning and initiating, the device is not available for otheractivities. Opening two receive windows may consume more power thanopening a single receive window. More importantly, when the antennaand/or the RF front end is occupied for such receiving times, the radioportion of the device is not able to do other functions due to themultiplexed timing scheme used in BT. This result may reduce thebandwidth efficiency of the device. The problem may compounded when thedevice has other wireless communication capabilities that it needs toaddress, such as classic BT, wireless local area network (WLAN) and/orcellular communication (e.g. long term evolution, commonly known asLTE).

It would be advantageous to combine the operations of scanning andinitiating into a single receive window opening for a BLE device. Sincethere is no prohibition in the BT 4.0 specification to use just onereceive window, there is no reason why the BLE device could not send outa connection request (initiation) while the device is scanning foradvertisers. If the received advertiser address is one that the devicewants to make a connection, the BLE device could always send out aconnection request, instead of a scan request. This allows only onereceive window to be needed to make a BLE connection, instead of tworeceive windows, yet remain compliant with the BT 4.0 standard. A numberof advantages may be obtained with concurrent scanning and initiation,including saving bandwidth and/or reducing power consumption.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram showing a wireless communication system inaccordance with one embodiment for practicing the present invention.

FIG. 2 is a block diagram showing an embodiment of a single modeBluetooth wireless communication system that employs separate units forclassic BT and BLE in accordance with one embodiment for practicing thepresent invention.

FIG. 3 is a block diagram showing an embodiment of a dual mode Bluetoothwireless communication system that employs one Bluetooth controller forboth classic BT and BLE in accordance with one embodiment for practicingthe present invention.

FIG. 4 is a block schematic diagram showing a host and a dual modeBluetooth controller, in which the Bluetooth controller includes a PHYlayer and a LINK layer in accordance with one embodiment for practicingthe present invention.

FIG. 5 is an illustration of a timing diagram depicting a BLE advertiseractivity during an advertising event in accordance with one embodimentfor practicing the present invention.

FIG. 6 is an illustration of a timing diagram depicting a connectionactivity during a connection event in accordance with one embodiment forpracticing the present invention.

FIG. 7 is a prior art state diagram showing the five states specifiedfor BLE operations under the Bluetooth 4.0 specification.

FIG. 8 is a state diagram showing the combining of the scanning andinitiating states to allow one receive window for BLE operations inaccordance with one embodiment for practicing the present invention.

FIGS. 9A and 9B show a flow chart of processing steps associated withthe initiating and scanning activities using one receive window inaccordance with one embodiment for practicing the present invention.

FIG. 10 is a diagram showing the combining of initiating white list andscanning white list in accordance with one embodiment for practicing thepresent invention.

FIG. 11A illustrates functional relationship of using active scan withnon-directed advertising packets in accordance with one embodiment forpracticing the present invention.

FIG. 11B illustrates functional relationship of using active scan withdirected advertising packets in accordance with one embodiment forpracticing the present invention.

FIG. 11C illustrates functional relationship of using passive scan withnon-directed advertising packets in accordance with one embodiment forpracticing the present invention.

FIG. 11D illustrates functional relationship of using passive scan withdirected advertising packets in accordance with one embodiment forpracticing the present invention.

FIG. 12 shows a prior art timing diagram when separate windows areutilized for scanning and initiating.

FIG. 13 show a timing diagram that combines the scanning and initiatingstates into a single window in accordance with one embodiment forpracticing the present invention.

FIG. 14 shows a timing diagram that is a hybrid of the two techniquesshown in FIGS. 12 and 13, in which only one receiving window for theinitiating state is used, but in which a second window for scanning isopen when a scanning function is needed, in accordance with analternative embodiment for practicing the present invention.

FIG. 15 is a circuit block diagram showing one hardware implementationto provide the PHY and LINK layers that operate with a host inaccordance with one embodiment for practicing the invention.

DETAILED DESCRIPTION OF THE INVENTION

The embodiments of the present invention may be practiced in a varietyof wireless communication devices that operate in a wireless Bluetooth(BT) environment or network. The examples described herein pertain todevices that operate within the Bluetooth low energy (BLE) specification(also BT standard and/or protocol) in the 2.4 GHz ISM band and utilizingone of the IEEE 802.11 protocols (e.g. 802.11a/b/g/n). However, theinvention may be readily adapted to other standards, protocols,frequency bands, etc., where communications links are established usingmultiple receiving states where multiple receiving windows may becompressed into a lesser number of receiving windows. Furthermore, theembodiments of the invention described below are implemented in a LINKlayer of a wireless communication device. However, in other embodiments,the application of the invention need not be limited only to the LINKlayer.

FIG. 1 illustrates one environment for practicing an embodiment of thepresent invention. FIG. 1 shows a communication system 10 that includesa plurality of base stations (BS) and/or access points (AP) 11-13 (an APmay be a personal control point or PCP), a plurality of wirelesscommunication devices 20-27 and a network hardware component 14. Thewireless communication devices 20-27 may be laptop computers 20 and 24,personal digital assistants 21 and 27, personal computers 23 and 26,cellular telephones 22 and 25, and/or any other type of device thatsupports wireless communications.

The base stations or access points 11-13 may be operably coupled tonetwork hardware 14 via respective local area network (LAN) connections15-17. Network hardware 14, which may be a router, switch, bridge,modem, system controller, etc., may provide a wide area network (WAN)connection 18 for communication system 10. Individual base station oraccess point 11-13 generally has an associated antenna or antenna arrayto communicate with the wireless communication devices in its area.Typically, the wireless communication devices register with a particularbase station or access point 11-13 to receive services withincommunication system 10. For direct connections (i.e., point-to-pointcommunications), wireless communication devices may communicate directlyvia an allocated channel.

Typically, base stations are used for cellular telephone systems(including 3G and 4G systems) and like-type systems, while access pointsare used for in-home or in-building wireless networks. Regardless of theparticular type of communication system, each wireless communicationdevice includes a built-in radio and/or is coupled to a radio. The radioincludes a linear amplifier and/or programmable multi-stage amplifier toenhance performance, reduce costs, reduce size, and/or enhance broadbandapplications. The radio also includes, or is coupled to, an antenna orantennas having a particular antenna coverage pattern for propagating ofoutbound RF signals and/or reception of inbound RF signals. In someinstances, the antennas may be directional antennas.

One or more of the shown devices may include circuitry and/or softwarewhich allows the particular device to communicate using BT communicationsystem technology with each other or with proximal BT devices 50-57.Generally with BT, the range is much shorter than typical WLAN links.The BT communication link may utilize various versions of the BTspecification, including the afore-mentioned Bluetooth 4.0specification. The particular portion of the specification that pertainsto the present invention is the Bluetooth low energy (BLE) portion ofthe specification. Although BLE may operate in conjunction withclassical BT, BLE does have a functional difference in the applicationof the protocol for establishing a communication link between two ormore BLE compatible devices.

FIG. 2 illustrates a case when classic BT and BLE systems areimplemented separately. Thus, host 100 operates with a classic BTcontroller 103 and host 101 operates with a separate BLE controller 104.The BLE system of host 101 and controller 104 is an example of a singlemode BLE system.

FIG. 3 illustrates a dual mode device, in which host 110 operates with adual mode BT controller 111 that includes both a classic BT controller103 and BLE controller 104. With a dual mode controller, host 110 maycommunicate with other respectively compatible devices using eitherclassic BT or BLE.

The classic BT system of controller 103 typically uses a Link ManagementProtocol (LMP) to communicate with other classic BT compatible devices,in which both Basic Rate (BR) and Enhanced Data Rate (EDR) may beapplicable for data transfer. During typical operation of a classic BTdevice, a physical radio channel is shared by a group of devices thatare synchronized to a common clock and frequency hopping pattern. Onedevice provides the synchronization reference and is known as the masterand all other devices are synchronized as slaves. A group of devicessynchronized in this fashion form a piconet. This is the fundamentalform of communication in the classic BT BR/EDR wireless technology.

The physical channel is sub-divided into time units known as slots. Datais transmitted between classic BT devices in packets that are positionedin these slots. Frequency hopping takes place between the transmissionand/or reception of packets. Classic BT technology provides the effectof full duplex transmission through the use of a Time-Division Duplex(TDD) scheme. Above the physical channel, there is a layering of linksand channels and associated control protocols. The hierarchy of channelsand links from the physical channel upwards is typically comprised ofphysical channel, physical link, logical transport, logical link andL2CAP channel, which hierarchy is illustrated in more detail in FIG. 4.

Within a physical channel, a physical link is formed between a masterdevice and slave device. The physical link provides bidirectional packettransport between the master and slave devices. Since a physical channelcould include multiple slave devices, there are restrictions on whichdevices may form a physical link. There is a physical link between eachslave and the master. Physical links are not formed directly between theslaves in a piconet.

The physical link is used as a transport for one or more logical linksthat support unicast synchronous, asynchronous and isochronous traffic,and broadcast traffic. Traffic on logical links is multiplexed onto thephysical link by occupying slots assigned by a scheduling function inthe resource manager. The LMP protocol for the baseband and physicallayers is carried over logical links in addition to user data. Devicesthat are active in a piconet have a default asynchronousconnection-oriented logical transport that is used to transport the LMPprotocol signaling. The Link Manager function uses LMP to control theoperation of devices in the piconet and provide services to manage thelower architectural layers.

Above the baseband layer, the L2CAP (Logical Link Control and AdaptionProtocol) layer provides a channel-based abstraction to applications andservices. It carries out segmentation and reassembly of application dataand multiplexing and de-multiplexing of multiple channels over a sharedlogical link. L2CAP has a protocol control channel that is carried overthe default ACL logical transport. Application data submitted to theL2CAP protocol may be carried on any logical link that supports theL2CAP protocol.

Although both classic BT and BLE operate in the 2.4 GHz ISM band andtypically utilize one of the IEEE 802.11 communication protocols (e.g.802.11a/b/g/n), the link protocols are different between the classic BTand BLE. Both classic BT and BLE may utilize aspects of time divisionmultiple access (TDMA) and frequency division multiple access (FDMA).Typically a device has only one radio, so that the radio may only eithertransmit or receive at any one given time (e.g. TDMA). In any onepiconet, a master may only address one slave at a time (e.g. TDMA). Bothclassic BT and BLE techniques channel hop allowing for multiple radiosto be operating simultaneously (e.g. FDMA). For BLE, one version usesthree (3) channels as advertising channels and thirty-seven (37) as datachannels.

The physical channel is sub-divided into time units known as events.Data is transmitted between BLE devices in packets that are positionedin these events. Two types of events are known as advertising events andconnection events. Devices that transmit advertising packets on theadvertising PHY channels are referred to as advertisers. Devices thatreceive advertising on the advertising channels without the intention toconnect to the advertising device are referred to as scanners. Devicesthat seek connections are referred to as initiators. The operation andimplementation of BLE in respect to practicing the invention are furtherdescribed later in the description.

FIG. 4 shows one example embodiment for implementing a BLE device indual mode operation. However, the BLE portion may be utilized in asingle mode BLE device as well. In FIG. 4, a radio portion, shown asradio 151, provides the RF front end for communicating with other BTdevices. Radio 151 generally includes one transmitter and receiver fortransmitting and receiving, as well as conversion between RF andbaseband. Generally, radio 151 forms the physical (PHY) layer 150 ofcontroller 111. It is to be noted that other embodiments may havemultiple radio stages (e.g. multiple transmitters and or multiplereceivers).

A link controller 141 for classic BT and link controller 142 for BLE areused to link radio 151 to a baseband processing device, shown asbaseband resource manager 143. A link manager 144 for classic BT usingLink Management Protocol (LMP) and link manager 145 using the LINK layerProtocol (LL) for BLE for communicating with remote BT devices are usedto link baseband resource manager 143 to host 110, via channel manager130. A L2CAP manager 131 for the L2CAP layer may be utilized withclassic BT connection. The link controllers 141, 142, baseband resourcemanager 143 and link managers 144, 145 generally form the LINK layer 140of controller 111.

Host 110 may include other functional units, other than channel manager130 for providing various functions for the L2CAP layer and above. Someof these functions are shown as Security Manger Protocol (SMP) unit 132,Attribute/Generic Attribute Protocol (ATT/GATT) unit 133 and ServiceDiscovery Protocol (SDP) unit 134. Other functional elements may bepresent in host 110 other than those units shown in FIG. 4. Furthermore,detailed workings of classic BT and BLE pertaining to the variousfunctional units shown in FIG. 4 may be obtained from theafore-mentioned Bluetooth 4.0 specification.

The host 110 in FIG. 4 is shown coupled to an applications stack or unit112, that provides one or more desired applications for operating thehost 110 to provide classic BT and/or BLE communications with one ormore remote devices. In some instances, the applications may be residentwithin host 110 itself. In other embodiments, the functions of the hostand applications may be present in the controller 111.

As noted above in reference to BLE operation, BLE uses two types ofevents, which are known as advertising events and connection events.Devices that transmit advertising packets on the advertising PHYchannels are referred to as advertisers. Devices that receiveadvertising on the advertising channels without the intention to connectto the advertising device are referred to as scanners. Devices that seekconnections are referred to as initiators. Transmissions on theadvertising PHY channels occur in advertising events.

As shown in diagram 200 of FIG. 5, at the start of each advertisingevent 201, the advertiser sends an advertising packet corresponding tothe advertising event type. If the scanner sends out a scan request tothe advertiser on the same advertising PHY channel, the advertiser mayrespond with a scan response. The advertising PHY channel may change onthe next advertising packet sent by the advertiser in the sameadvertising event. The advertiser may end the advertising event at anytime during the event. The subsequent advertising event 202 is alsoshown in diagram 200. BLE devices may fulfill the entire communicationin the case of unidirectional or broadcast communication between two ormore devices using advertising events. They may also use advertisingevents to establish pair-wise bi-directional communication between twoor more devices using data channels.

As shown in diagram 210 of FIG. 6, a device that desires to form aconnection to another device listens for connectable advertisingpackets. Such devices are referred to as initiators. If the advertiseris using a connectable advertising event, an initiator may make aconnection request using the same advertising PHY channel on which itreceived the connectable advertising packet, as shown during advertisingevent 211. The advertising event is ended and connection events begin ifthe advertiser receives and accepts the request for a connection to beinitiated. Once a connection is established, the initiator becomes themaster device in a piconet and the advertising device becomes the slavedevice. Connection events, shown as connection events 212 and 213, areused to send data packets between the master (M) and slave (S) devices.In connection events, channel hopping occurs at the start of eachconnection event. Within a connection event, the master and slavealternate sending data packets using the same data PHY channel. Themaster initiates the beginning of each connection event and may end eachconnection event at any time.

FIG. 7 shows a diagram of a state machine 300 that illustrates the five(5) states of the LINK layer for BLE devices, as currently specified bythe BT 4.0 specification. The five states are standby 301, advertising303, scanning 302, initiating 304 and connection 305 states. LINK layerstate machine 300 allows only one state to be active at a time. The LINKlayer may have multiple instances of the LINK layer state machine 300.

The LINK layer in the standby state does not transmit or receive anypackets. Standby state 301 may be entered from any other state. Inadvertising state 303, the LINK layer transmits advertising channelpackets and possibly listens to and responds to responses triggered bythese advertising channel packets. A device in advertising state 303 isknown as an advertiser. Advertising state 303 may be entered fromstandby state 301. The LINK layer in scanning state 302 listens foradvertising channel packets from devices that are advertising. A devicein scanning state 302 is referred to as a scanner. Scanning state 302may be entered from standby state 301.

The LINK layer in initiating state 304 is listening for advertisingchannel packets from a specific device(s) and responds to these packetsto initiate a connection with another device. A device in initiatingstate 304 is known as an initiator. Initiating state 304 may be enteredfrom standby state 301. Connection state 305 may be entered either frominitiating state 304 or advertising state 303. A device in connectionstate 305 is known as being in a connection. When in connection state305, a device may be a master or a slave. When the device entersconnection state 305 from initiating state 304, the device in connectionstate 305 is the master. When entered from advertising state 303, thedevice in connection state 305 is a slave.

The LINK layer may optionally support multiple state machines. If itdoes support multiple state machines, the following restrictions apply.The LINK layer in connection state 305 may not operate as master andslave at the same time. When in connection state 305 as a slave, onlyone connection is permitted. When in connection state 305 as a master,multiple connections are permitted. The LINK layer may not operate ininitiating state 304, if the LINK layer is already operating inconnection state 305 as a slave.

Because BT 4.0 specification requires BLE scanning and initiating statesto be two independent and completely separate activities, a BLE devicewhich is compliant to the BT 4.0 specification does either scanning orinitiation. With prior art practice, this separation of scanning andinitiating states requires the device, which is the master, to open thereceive window twice to monitor the traffic. In order to make aconnection (enter connection state 305), the device needs to open areceive window in scanning state 302 to scan for advertisers and openthe receive window again in initiating state 304 to initiate (send) aconnection request. This implies that during these two periods, theradio and antenna are committed to a BLE receiving mode and may not beavailable for other activities, which may include classic BT, WLANand/or cellular communication (e.g. 3G, LTE, 4G). FIG. 12 shows a timingdiagram 500 that illustrates the presence of having two separate receivewindows, one receive window for scanning and a separate receive windowfor initiating. The initiating window may precede or follow the scanningwindow.

Referring to FIG. 8, a state machine 310 to practice one embodiment ofthe invention is shown. State machine 310 has the same five states notedin FIG. 7, as required by the BT 4.0 specification. However, in thisinstance, scanning and initiating operations are combined into a singlereceive window (as illustrated by the enclosure of the two states 302and 304). It is to be noted that there exists no physical constraint whythe master could not also send out a connection request while it isscanning for advertisers, if the received advertiser address is one ofthe devices that the master device wants to make connection to.Combining the two activities of scanning and initiating would requireonly one receive window, instead of two. Having one receive window doesnot violate the BT 4.0 specification for BLE operation, since bothscanning and initiating functions are still being performed by the BLEdevice. Utilizing one receive window may result in lower powerconsumption, which is advantageous for BLE devices operating on batterypower. Furthermore, having one less receiving window also allows thedevice to perform other functions during the period of the now absentsecond window, thereby possibly improving bandwidth efficiency. FIG. 13shows a timing diagram 510 in which the scanning and initiating statesare combined into a single receive window. Comparing the one windowtiming diagram 510 to the two window timing diagram 500 of FIG. 12illustrates the significant advantage obtained by having one receivewindow opening to provide concurrent scanning and initiating operations.

The BLE portion of the BT 4.0 specification uses a “white list” (WL) tosetup scanning and connection filtering policies. When the policy isenabled (e.g. the white list is in use), if the device address receivedin an advertisement packet is in the white list, then appropriate actionis taken for scanning or initiating a connection. If the received deviceaddress does not match with a content of the white list, or does notmatch a preprogrammed peer address, no further action is taken for thedevice with that address. The white list filtering is configured by thehost and used by the LINK layer to filter advertisers, scanners orinitiators. The white list allows the host to configure the LINK layerto act on a request without awakening the host. The embodiments of theinvention that combine the scanning and initiating states into onereceiving window operation also uses a white list in accordance with theBT 4.0 specification, but modified to accommodate two white lists, onefor scanning and one for initiating.

FIG. 9 (shown on two sheets as 9A and 9B) depicts a flow chart thatshows an example method in implementing the concurrent scanning andinitiating operation according to one embodiment for practicing theinvention. The concurrent scanning and initiating operation shownutilizes both a scanning white list and an initiating white list.Furthermore, scenarios that may result from the concurrent scanning andinitiating operation of FIG. 9 is further categorized in the tables ofFIGS. 11A-D. The method shown in FIG. 9 takes into account the use ofactive scan or passive scan for both non-directed and directedadvertisement packets, as well as the use of one, both or no whitelist(s). Directed advertisement pertains to a condition when theadvertisement packet is directed to a particular address (e.g. thepacket address matches the receiver's device address), whereasnon-directed advertisement pertains to a condition when theadvertisement packet is broadcast without a directed address. Peeraddress pertains to a preprogrammed peer address of other devices storedin the receiving device. Active scan pertains to a scanning situationwhen a response may be forthcoming, whereas passive scan pertains to ascanning situation where the advertisement packet is scanned, but noresponse is to be initiated by the receiving device.

Thus, as illustrated in FIG. 9, when the receiving window is opened, theconcurrent BLE scanning and initiating operation starts (block 400),allowing the advertising packet(s) sent from the advertiser to bereceived by the BLE device. The operation then depends on if one or bothof the white lists is/are used to filter the advertisement packet. Ifneither white list is used (block 401), the operation determines if theadvertisement packet is a directed advertisement packet (block 409). Ifdirected, the address in the packet is checked for the initiatingaddress that corresponds to the device (block 410) and if there is amatch, the method progresses to check for a peer address match (block411). If there is a peer address match (block 411), a connection requestis sent out (block 404).

If at block 410, the initiating address check does not match the deviceaddress, the packet is filtered out (block 415) at the LINK layer,typically without notifying the high-level controller and/or the host.At the peer address check at block 411, if the packet does not match oneof the peer addresses stored in the device, the packet reception isreported to the higher-level controller, but no response is sent out(block 412) from the receiving device.

Alternatively, at block 409, if the packet is a non-directedadvertisement packet, the peer address is checked (block 402) and if amatch occurs, a connection request is sent out (block 404). If there isno peer address match at block 402, a scan request is sent out (block407) from the device if active scan is employed. If passive scan isemployed for the device (block 405), then nothing is sent out for thescanning operation (block 408), but the packet reception is reported tothe controller (block 412).

If at block 401, at least one white list is used, the method thendetermines if both the scanning white list and the initiating white listare used. If both white lists are used, the method then checks todetermine if the advertisement packet is a directed advertisement packet(block 414). If the packet is a non-directed advertisement packet (block414), then the initiating white list is checked (block 403). If thepacket contains an initiating address that matches an address entry inthe initiating white list (block 403), a connection request is sent out(block 404). If block 403 does not result in a match, the scanning whitelist is checked next. If the address in the packet matches an addressentry in the scanning white list (block 406), the method progresses todetermine if the scan operation is active or passive (block 405) andresponds accordingly as shown at block 407 or 412 and described above.

If at block 414, the packet is a directed advertisement packet, theaddress in the directed packet is checked (block 416) and, if it matchesthe device address, the initiating white list is checked for a matchingaddress (block 417). If at block 416, the address does not match thedevice address, then the packet is filtered out (block 415). If theinitiating address of the directed advertisement packet matches an entryof the initiating white list (block 417), a connection request is sentout (block 404). If there is no match in the initiating white list atblock 417, the method proceeds to check if both white lists are used(block 418). Note that this check is made at block 418, since there isan alternate entry into block 416 through path “C.”

If both white lists are being used (block 418), the method has alreadychecked for the initiating address match and found none, so the check isnow made with the scanning white list (block 419). If the packet addressmatches an entry in the scanning white list, then the method progressesto block 405 where appropriate response (to block 407 or 412) is made atblock 405, depending on which of the scan (active or passive) is beingused. If there is no match in the scanning white list at block 419, thepacket is filtered out (block 415).

Note that at block 418, if both white lists are not being utilized, thenonly the initiating white list is being used. If only the initiatingwhite list is being used at block 418, the method progresses to block405 and the resulting path is to block 407 or block 412, depending onthe type of scan (active or passive) being employed.

Returning to block 413, if only one white list is being utilized, themethod progresses to check which white list is being used (block 420).If only the initiating white list is being used, then the method checksto determine if the advertisement packet is a directed advertisementpacket (block 421). If direct, the method progresses to check for theinitiating address match at block 416 and further transcends through thepaths from block 416 as described above. If the packet is a non-directedpacket (block 421), the initiating white list is checked for a match(block 422). If the address contained in the packet matches an entry inthe initiating white list, then a connection request is sent out (block404). If there is no match, then the method progresses to block 405 andproceeds on the path from block 405, depending on whether active orpassive scan is being used.

Returning to block 420, if only the scanning white list is beingutilized, then a check is made to determine if the advertisement packetis a directed or non-directed packet (block 423). If the advertisementpacket is a directed packet, the method progresses to block 410 andfollows the decision branches from block 410 as described above. If theadvertisement packet is a non-directed packet, then the methodprogresses to block 406 to make a scanning white list check and proceedfrom block 406 as previously described based on the whether there is ascanning white list match or not.

It is apparent from the flow diagram of FIG. 9, that when the receivingwindow opens, the process initially determines which white list(s)is/are being used (or not at all), followed by a determination ofdirected or non-directed advertisement packet. The method then checksthe packet for attributes pertaining to the initiating operation first,followed by attributes pertaining to the scanning operation. The finalportion of the method determines a response based on whether activescanning or passive scanning is being utilized.

Furthermore, it is to be noted that the particular process asillustrated in the flow diagram may be implemented in a variety of ways,including hardware, software, firmware or combinations thereof. In oneembodiment the method of the flow diagram is implemented as an algorithmcontained in a software routine. In another embodiment, the method ofthe flow diagram is implemented in hardware. It is to be noted that theflow diagram of FIG. 9 is just one example for implementing theinvention and that other methods may be implemented as differentembodiments for practicing the invention. For example, instead ofperforming the checks of initiating first followed by checks forscanning for a received packet, the two processes may be reversed. Thatis, in other embodiments, scanning checks are made first followed byinitiating checks for a received advertisement packet.

In the flow diagram of FIG. 9, the two white lists are noted as separatewhite lists. Because of the concurrent operation of performing bothscanning and initiating within the one open receive window, ademarcation is needed for accessing entries in the two white lists. Theentries for the two white lists may be separated into two separate whitelists or they may be combined together, but tagged for entry in each ofthe white lists. Accordingly, as shown in FIG. 10, in one instance twoseparate white lists are maintained as separate white lists 421, 422.The two separate white lists may be mapped to separate storage (e.g.memory) modules or units (as shown to the right in FIG. 10) or mapped todifferent locations in one storage module or unit 420. Alternatively, asingle white list 423 may be used, wherein tags are used to identifywhich white list or lists a particular entry belongs. For example, inone embodiment, Tag1 and Tag2 are used, where each Tag# is representedby a bit. Thus, setting the Tag1 bit designates that a particular entrybelongs in the initiating white list and setting Tag2 bit designatesthat a particular entry belongs in the scanning white list. Setting bothtags designates that a particular entry belongs in both white lists. Inone embodiment, in addition to 48 bit of address and one bit ofpublic/random address indicator, two bits are added to the entry as Tag1and Tag2 attributes. In other embodiments, firmware may be used todynamically configure the attribute.

It is to be appreciated that other techniques may be readily used to setentries for one or both white lists.

FIGS. 11A-D show tables for implementing the concurrent scanning andinitiating activities as described above in reference to the method ofFIG. 9. The tables identify the various situations encountered in thedecision process for the flow diagram of FIG. 9 and the resultsobtained. The tables show conditions of using active scan or passivescan for both non-directed and directed advertisement packets. Theheadings for each table identify conditions when the advertisementpacket matches a preprogrammed peer address (first column), when thepacket address of a directed advertisement matches the receiver's deviceaddress (second column), when the advertising packet address matches anentry in the initiating white list WL (third column), when theadvertising packet matches the scanning WL (fourth column) and theexpected result from the device (fifth column). A disable (Dis) statusis used for a particular WL when that WL is not used (e.g. disabled).Note also that the initiating match only applies to directedadvertisement packets. An error condition in the Expected Result headingcorrelates to the filter out result of block 415 in FIG. 9.

Some examples of the concurrent scanning and initiation as implementedin the tables of FIG. 11 are described below and better understood whenapplied to the method illustrated in the flow diagram of FIG. 9:

With Active Scan Enabled:

1. If both scanning and initiation white list policy are disabled (Dis):

In this case if the received advertiser address matches with apreprogrammed peer address, a connection request is sent out if aconnectable advertisement packet is received. If a directedadvertisement packet is received, in addition to the peer address match,the received initiation (“init”) address also has to match with thereceiver's device address in order for the receiver to send out aconnection request. Otherwise, a scan request is sent out and theadvertisement packet is a connectable (non-directed) advertisementpacket.

2. If the initiation white list is enabled and the scanning white listis not enabled:

In this case if the received connectable (non-directed) advertiseraddress is in the white list, then a connection request is sent out.

If the received directed advertiser address is in the initiation whitelist and received initiation address also matches, a connection requestis sent out.

If the received connectable (non-directed) advertiser address is not inthe initiation white list, a scan request is sent out.

If the received directed advertiser address is not in the initiationwhite list, but the received initiation address matches, the scannerreports the received message to the controller and sends nothing out.

If the initiation address in the received direct advertisement packetdoes not match with the scanner's own address, regardless whether apreprogrammed peer address matches or not, or whether the receivedadvertiser address is in the white list or not, the device reports areceive error and sends nothing out.

3. Initiation white list is not enabled, scanning white list is enabled:

If the received connectable (non-directed) advertiser address matcheswith a preprogrammed peer address, a connection request is sent out.

If the received connectable (non-directed) advertiser address does notmatch with a preprogrammed peer address, but is in the scan white list,a scan request is sent out.

If the received connectable (non-directed) advertiser address does notmatch with a peer address, and is not in the white list, the devicesends nothing out.

If the received directed advertiser initiation address matches withscanner's own address and the advertiser address also matches apreprogrammed peer address, a connection request is sent out.

If the received directed advertiser initiation address matches withscanner's own address and the advertiser address does not match apreprogrammed peer address, the scanner reports the received packet tothe controller and sends nothing out.

If the received directed advertiser initiation address does not matchwith the scanner's own address, the scanner will report an error to thecontroller and sends nothing out.

4. Both initiation and scanning white list enabled:

If the received connectable (non-directed) advertiser address is in theinitiation white list, a connection request is sent out. If the receivedadvertiser address is not in the initiation white list but is in thescanner white list, then a scan request is sent out. If neither is true,the advertisement packet is ignored.

For directed advertisement, if the received initiation address matchesthe scanner device's own address and received advertiser address is inthe initiation white list, a connection request is sent out.

For directed advertisement, if the received initiation address matchesthe scanner device's own address but the received advertiser address isnot in the initiation white list, the scanner passes the received packetto the controller and sends nothing out.

For directed advertisement, if the received initiation address does notmatch to the scanner's own address, the scanner reports an error to thecontroller and sends nothing out.

In all other cases, nothing is sent out.

With Passive Scan Enabled:

5. Both scanning and initiation white list policy are disabled:

In this case, if the received connectable (non-directed) advertiseraddress matches with a preprogrammed peer address, a connection requestis sent out. For directed advertisement, additionally the receivedinitiation address has to match the scanner's address to send out aconnection request. Otherwise, the device sends out nothing.

6. Initiation white list is enabled, scan white list is not enabled:

If the received connectable (non-directed) advertiser address is in theinitiation white list a connection request is sent out.

If the received directed advertiser address is in the initiation whitelist and at the same time the received initiation address matches thescanner's own address, a connection request is sent out.

If the received connectable (non-directed) address is not in theinitiation white list, the scanner will report the advertisement packetto the host but nothing is sent out to the advertiser.

If the received initiation address of the direct advertiser address doesnot match the scanner's own address, regardless if the receivedadvertiser address is in the white list or not, the device reports areceive error and sends nothing out.

If the initiation address in the received directed advertisement packetmatches with the scanner's own address, but the received advertiseraddress is not in the initiation white list, the scanner passes thereceived packet to the host but sends nothing out to the advertiser.

7. Initiation white list is not enabled, scanning white list is enabled:

If the received connectable (non-directed) advertiser address matcheswith a preprogrammed peer address, a connection request is sent out.

If the received connectable (non-directed) advertiser address does notmatch with a preprogrammed peer address, but is in the scan white list,the scanner passes the received packet to the host and sends nothing outto the advertiser.

If the received connectable (non-directed) advertiser address does notmatch with a preprogrammed peer address, and is not in the scan whitelist, the device ignores the advertisement packet and sends nothing out.

If the received directed advertiser initiation address matches with thescanner's address and the advertiser address also matches apreprogrammed peer address, a connection request is sent out.

If the received directed advertiser initiation address matches with thescanner's address and the advertiser address does not match apreprogrammed peer address, the scanner reports the received packet tothe host but sends nothing out to the advertiser.

If the received directed advertiser initiation address doesn't matchwith the scanner's address, the scanner will ignore this packet andsends nothing out to the advertiser.

8. Both initiation and scanning white list enabled:

If the received connectable (non-directed) advertiser address is in theinitiation white list, a connection request is sent out. If the receivedadvertiser address is not in the initiation white list but is in thescanner white list, the scanner passes the received packet to the hostbut sends nothing out to the advertiser. If the received advertiseraddress is in neither white lists, the scanner ignores thisadvertisement packet and nothing is sent to the advertiser.

For directed advertisement, if the received initiation address matchesthe scanner's own address and the received advertiser address is in theinitiation white list, a connection request is sent out.

For directed advertisement, if the received initiation address matchesthe scanner's own address but the received advertiser address is not inthe initiation white list, the scanner passes the received packet to thehost but sends nothing out to the advertiser.

For directed advertisement, if the received initiation address does notmatch with the scanner's own address, the scanner ignores thisadvertisement packet and sends nothing out to the advertiser.

As noted above, FIG. 12 shows the prior art technique of opening twoseparate receiving windows for a BLE device for each of the scanning andinitiating operations to make a connection to an advertiser. Also asdescribed above, FIG. 13 shows the concurrent scanning and initiatingoperation of the present invention, in which one receive window isopened to perform both scanning and initiating operations.

FIG. 14 shows a timing diagram 511 which is a hybrid technique that isan alternative embodiment for practicing the invention. In the hybridtechnique, a single initiating window is utilized to monitor theadvertisement packets. When an advertisement requiring a scan request isnoticed while performing the initiating operation, the device opens aseparate window to perform the scanning operation. The device thenapplies the prior art technique of using separate receive windows forinitiating and scanning. After another advertisement from the sameadvertiser is received or a timeout period lapses, the device resorts tothe single receive window mode. With this hybrid technique, some amountof power conservation and bandwidth efficiency are observed, but not tothe extent of the single receive window mode shown in FIG. 13.

One advantage of the hybrid technique is that it may be readily adaptedfor use within devices that have hardware geared to the two windowtechnique (e.g. of FIG. 12). By making firmware adjustments, the hybridtechnique may be implemented in existing integrated circuit chips withslight modifications. In one embodiment, the concurrent scanning andinitiating technique utilizing only one receive window (e.g. of FIG. 13)is designed into a new integrated circuit chip that employs dedicatedhardware, although in other embodiments, the one receive windowtechnique may be implemented in hardware, software, firmware, or acombination thereof.

FIG. 15 is a schematic block diagram illustrating part of a wirelesscommunication portion 600 of a wireless device that includes atransmitter (TX) 601, receiver (RX) 602, local oscillator (LO) 607 andbaseband module 605. Baseband module 605 provides baseband processingoperations. In some embodiments, baseband module 605 is or includes adigital-signal-processor (DSP). Baseband module 605 is typically coupledto a host unit (such as the afore-mentioned host unit for BToperations), applications processor or other unit(s) that provides BToperational processing for the device and/or interface with a user. Inone embodiment, the hardware diagram of FIG. 15 is representative of adevice that provides BT functionality and specifically BLE compatiblefunctionality described above.

In FIG. 15, a host unit 610 is shown. For example, host 610 mayrepresent host 101, 110 of a BLE device, while device portion 600 isutilized to provide the radio (e.g. RF front end) and basebandfunctions. The radio portion may be strictly for single mode BLE, dualmode BT/BLE, or it may include other wireless operations such as WLAN(e.g. WiFi) and/or cellular or satellite communications. With BToperations, device portion provides the PHY layer and LINK layerfunctionality of BT/BLE controller, such as controller 111 shown in FIG.4. Any or all of the hardware shown in FIG. 15 may be incorporated inone or more of the wireless communication devices shown in FIG. 1.

A memory 606 is shown coupled to baseband module 605, which memory 606may be utilized to store data, as well as program instructions thatoperate on baseband module 605. Various types of memory devices may beutilized for memory 606. It is to be noted that memory 606 may belocated anywhere within device portion 600 and, in one instance, it mayalso be part of baseband module 605.

Transmitter 601 and receiver 602 are coupled to an antenna 604 viatransmit/receive (T/R) switch module 603. T/R switch module 603 switchesthe antenna between the transmitter and receiver depending on the modeof operation. In other embodiments, separate antennas may be used fortransmitter 601 and receiver 602, respectively. Furthermore, in otherembodiments, multiple antennas or antenna arrays may be utilized withdevice 600 to provide antenna diversity or multiple input and/ormultiple output, such as MIMO, capabilities.

At frequencies in the lower gigahertz range, omni-directional antennasprovide adequate coverage for communicating between wireless devices.Thus, at frequencies about 2.4-5 GHz, one or more omni-directionalantenna(s) is/are typically available for transmitting and receiving.However, at higher frequencies, directional antennas with beamformingcapabilities are utilized to direct the beam to concentrate thetransmitted energy, due to the limited range of the signal. In theseinstances, antenna arrays allow for directing the beam in a particulardirection.

Outbound data for transmission from host unit 610 are coupled tobaseband module 605 and converted to baseband signals and then coupledto transmitter 601. Transmitter 601 converts the baseband signals tooutbound radio frequency (RF) signals for transmission from device 600via antenna 604. Transmitter 601 may utilize one of a variety ofup-conversion or modulation techniques to convert the outbound basebandsignals to outbound RF signal. Generally, the conversion process isdependent on the particular communication standard or protocol beingutilized.

In a similar manner, inbound RF signals are received by antenna 604 andcoupled to receiver 602. Receiver 602 then converts the inbound RFsignals to inbound baseband signals, which are then coupled to basebandmodule 605. Receiver 602 may utilize one of a variety of down-conversionor demodulation techniques to convert the inbound RF signals to inboundbaseband signals. The inbound baseband signals are processed by basebandmodule 605 and inbound data is output from baseband module 605 to hostunit 610.

LO 607 provides local oscillation signals for use by transmitter 601 forup-conversion and by receiver 602 for down-conversion. In someembodiments, separate LOs may be used for transmitter 601 and receiver602. Although a variety of LO circuitry may be used, in someembodiments, a PLL is utilized to lock the LO to output a frequencystable LO signal based on a selected channel frequency.

It is to be noted that in one embodiment, baseband module 605, LO 607,transmitter 601 and receiver 602 are integrated on the same integratedcircuit (IC) chip. Transmitter 601 and receiver 602 are typicallyreferred to as the RF front-end or radio. In other embodiments, one ormore of these components may be on separate IC chips. Similarly, othercomponents shown in FIG. 15 may be incorporated on the same IC chip,along with baseband module 605, LO 607, transmitter 601 and receiver602. In some embodiments, the antenna 604 may also be incorporated onthe same IC chip as well. Furthermore, with the advent of system-on-chip(SOC) integration, host devices, application processors and/or userinterfaces, such as host unit 610, may be integrated on the same IC chipalong with baseband module 605, transmitter 601 and receiver 602.

Additionally, although one transmitter 601 and one receiver 602 areshown, it is to be noted that other embodiments may utilize multipletransmitter units and receiver units, as well as multiple LOs. Forexample, diversity communication and/or multiple input and/or multipleoutput communications, such as multiple-input-multiple-output (MIMO)communication, may utilize multiple transmitters 601 and/or receivers602 as part of the RF front-end.

The utilization of a single receive (receiving) window (or a hybridwindow) to perform concurrent scanning and initiating for BLE operationshas a number of advantages, including lower power consumption andbandwidth efficiency. Lower power is obtained since only one receivewindow is used to provide both the initiating and scanning functions,instead of utilizing two receive windows. Bandwidth efficiency isobtained, because by allocating a period for only one window, timeallocation which have been needed for the second window may be allocatedto other functions or other devices in the network to transmit. Theinvention is applicable for BLE operations as specified in Version 4.0of the Bluetooth specification. However, the invention need not belimited to the particular version of the Bluetooth specification.Furthermore, the invention may be readily adapted for use with othercommunication protocols or standards that utilize more than one receivewindow, wherein the invention reduces the number of receive windowsutilized by a device by performing concurrent receiving operations.

Thus, concurrent scanning and initiation for BLE is described.

As may be used herein, the terms “substantially” and “approximately”provides an industry-accepted tolerance for its corresponding termand/or relativity between items. Such an industry-accepted toleranceranges from less than one percent to fifty percent and corresponds to,but is not limited to, component values, integrated circuit processvariations, temperature variations, rise and fall times, and/or thermalnoise. Such relativity between items ranges from a difference of a fewpercent to magnitude differences. As may also be used herein, theterm(s) “operably coupled to”, “coupled to”, and/or “coupling” includesdirect coupling between items and/or indirect coupling between items viaan intervening item (e.g., an item includes, but is not limited to, acomponent, an element, a circuit, and/or a module) where, for indirectcoupling, the intervening item does not modify the information of asignal but may adjust its current level, voltage level, and/or powerlevel. As may further be used herein, inferred coupling (i.e., where oneelement is coupled to another element by inference) includes direct andindirect coupling between two items in the same manner as “coupled to”.

The term “module” is used in the description of the various embodimentsof the present invention. A module includes a functional block that isimplemented via hardware to perform one or module functions such as theprocessing of one or more input signals to produce one or more outputsignals. The hardware that implements the module may itself operate inconjunction software, and/or firmware. As used herein, a module maycontain one or more sub-modules that themselves are modules.

The present invention has been described above with the aid of methodsteps illustrating the performance of specified functions andrelationships thereof. The boundaries and sequence of these functionalbuilding blocks and method steps have been arbitrarily defined hereinfor convenience of description. Alternate boundaries and sequences canbe defined so long as the specified functions and relationships areappropriately performed. Any such alternate boundaries or sequences arethus within the scope and spirit of the claimed invention. Further, theboundaries of these functional building blocks have been arbitrarilydefined for convenience of description. Alternate boundaries could bedefined as long as the certain significant functions are appropriatelyperformed. Similarly, flow diagram blocks may also have been arbitrarilydefined herein to illustrate certain significant functionality. To theextent used, the flow diagram block boundaries and sequence could havebeen defined otherwise and still perform the certain significantfunctionality. Such alternate definitions of both functional buildingblocks and flow diagram blocks and sequences are thus within the scopeand spirit of the claimed invention. One of average skill in the artwill also recognize that the functional building blocks, and otherillustrative blocks, modules and components herein, can be implementedas illustrated or by discrete components, application specificintegrated circuits, processors executing appropriate software and thelike or any combination thereof.

The present invention may have also been described, at least in part, interms of one or more embodiments. An embodiment of the present inventionis used herein to illustrate the present invention, an aspect thereof, afeature thereof, a concept thereof, and/or an example thereof. Aphysical embodiment of an apparatus, an article of manufacture, amachine, and/or of a process that embodies the present invention mayinclude one or more of the aspects, features, concepts, examples, etc.described with reference to one or more of the embodiments discussedherein. Further, from figure to figure, the embodiments may incorporatethe same or similarly named functions, steps, modules, etc. that may usethe same or different reference numbers and, as such, the functions,steps, modules, etc. may be the same or similar functions, steps,modules, etc. or different ones.

While particular combinations of various functions and features of thepresent invention have been expressly described herein, othercombinations of these features and functions are likewise possible. Thepresent invention is not limited by the particular examples andembodiments disclosed herein and expressly incorporates these othercombinations.

We claim:
 1. A method comprising: opening a receiving window in a deviceto receive a packet transmission according to a proximal wirelesstransmission protocol compliant with a Bluetooth Low Energy wirelessspecification; using the receiving window to identify an address of thepacket transmission to perform an initiating operation to connect to aremote device; using the receiving window to identify an address of thepacket transmission to perform a scanning operation; and performing boththe scanning operation and the initiating operation utilizing the samereceiving window while the receiving window is open, instead of openingtwo receiving windows to perform separate scanning and initiatingoperations.
 2. The method of claim 1, wherein the proximal wirelesstransmission protocol is based on a Bluetooth 4 specification.
 3. Themethod of claim 1, further comprising for the device to communicate witha second remote device using a second wireless transmission protocol,once the receiving window closes.
 4. The method of claim 1, wherein thepacket transmission is part of an advertisement packet transmitted froma Bluetooth Low Energy wireless specification compliant device.
 5. Themethod of claim 4, further comprising connecting to the remote device ina connection event transmitted from the Bluetooth Low Energy wirelessspecification compliant device.
 6. The method of claim 5, wherein anaddress in the advertisement packet is compared to an entry in aninitiating white list or an entry in a scanning white list.
 7. Themethod of claim 5, wherein an address in the advertisement packet iscompared to an entry in an initiating white list and an entry in ascanning white list.
 8. A method comprising: utilizing a LINK layeroperation to open a receiving window in a device to receive atransmitted advertisement packet that is transmitted in accordance witha Bluetooth Low Energy wireless specification; utilizing the LINK layeroperation to identify an address of the advertisement packet when thereceiving window is open to perform an initiating operation to connectto a remote device; utilizing the LINK layer operation to identify anaddress of the advertisement packet when the receiving window is open toperform a scanning operation; and performing both the scanning operationand the initiating operation utilizing the same receiving window whilethe receiving window is open, instead of opening two receiving windowsto perform separate scanning and initiating operations.
 9. The method ofclaim 8, wherein the advertisement packet is part of an advertisingevent transmitted from a Bluetooth Low Energy wireless specificationcompliant device.
 10. The method of claim 9, further comprisingconnecting to the remote device in a connection event transmitted fromthe Bluetooth Low Energy wireless specification compliant device. 11.The method of claim 10, further comprising using a filtering list tocompare a received address with addresses in the filtering list.
 12. Themethod of claim 10, further comprising using an initiating white listand a scanning white list to compare a received address with addressentries in at least one of the initiating or scanning white lists tofilter for addresses.
 13. The method of claim 12, wherein one filteringlist is used and attributes are attached to entries in the one filteringlist to identify if a particular entry belongs in one or both of theinitiating white list and scanning white list.
 14. An apparatuscomprising: a radio frequency front end to configured to function as aPhysical (PHY) layer for wireless communication; and a baseband modulecoupled to the radio frequency front end configured to function as aLINK layer for the wireless communication, the LINK layer configured to:open a receiving window in a device to receive a transmittedadvertisement packet that is transmitted in accordance with a BluetoothLow Energy wireless specification; identify an address of theadvertisement packet when the receiving window is open to perform aninitiating operation to connect to a remote device; identify an addressof the advertisement packet when the receiving window is open to performa scanning operation; and perform both the scanning operation and theinitiating operation utilizing the same receiving window while thereceiving window is open, instead of opening two receiving windows toperform separate scanning and initiating operations.
 15. The apparatusof claim 14, wherein the LINK layer is further configured to operatesthe apparatus as a Bluetooth Low Energy wireless specification compliantdevice and the advertisement packet is part of an advertising eventtransmitted from another Bluetooth Low Energy wireless specificationcompliant device.
 16. The apparatus of claim 15, wherein the LINK layeris further configured to initiate a connection to the remote device in aconnection event transmitted from the other Bluetooth Low Energywireless specification compliant device.
 17. The apparatus of claim 16,wherein the LINK layer is further configured to include a filtering listto compare a received address with addresses in the filtering list. 18.The apparatus of claim 16, wherein the LINK layer is further configuredto include initiating a white list and a scanning white list to comparea received address with address entries in at least one of theinitiating or scanning white lists to filter for addresses.
 19. Theapparatus of claim 18, wherein the LINK layer is further configured toinclude separate filtering lists for the initiating white list andscanning white list.
 20. The apparatus of claim 18, wherein the LINKlayer is further configured to include one filtering list withattributes attached to entries in the one filtering list to identify ifa particular entry belongs in one or both of the initiating white listand scanning white list.